Unscheduled or unexpected events, referred to herein as asynchronous events, can occur in cases of media streaming or downloading, e.g., over the Internet or other Internet Protocol (IP) based networks. Asynchronous events may occur during live broadcast or live streaming or during video on demand (VoD) content downloading. Asynchronous events are used for digital program insertion such as for advertisement and can also be used for applications such as emergency messaging and blackout management. Targeted advertisement is a revenue source in the current entertainment ecosystem, both on the Internet and in the Cable/IP television (IPTV) environment. In the Cable/IPTV environment, targeted advertisement insertion is standardized via SCTE-35 (via mark-up) and SCTE-30/130 (via advertisement server interaction), and is available from multiple vendors.
Schedule changes may occur in live events. For example, during the 2011 Canadian Grand Prix of Formula One racing, a heavy rainstorm hit the racing circuit and the race was stopped at about 30 minutes from start and then restarted after more than two hours. Such situations trigger schedule changes by broadcasters, for example to insert advertisement or other asynchronous events. The broadcasters may run alternative programming (e.g., advertisement) during the unexpected delay or after cancellation of the main broadcast event. In another example, if a soccer or hockey game score is a tie, the game goes into overtime. Overtime may last anywhere between minutes and hours (with several breaks) and scheduled content may be delayed or canceled. There is a need for an efficient adaptive streaming scheme to handle asynchronous events in such situations, such as to insert advertisement, emergency messaging, or blackout alerts.